1. Field of the Invention
This invention relates to a ball-shooting game machine such as a pachinko game machine. More specifically, it relates to a ball-shooting game machine which includes a special winning hole, called starter hole, for initiating a separate game when a game ball shot onto a game board surface enters the winning hole, and a separate game device for conducting the separate game.
2. Description of the Prior Art
In a pachinko game machine a ball shooter is provided for shooting game balls onto a game board surface, having one or more winning holes or other winning devices, and a plurality of nails or pins which interfere with and guide the balls' travel. The object of the game is to get the balls to enter a winning hole or other winning device. It is well known that a probability of producing winning balls; i.e., getting balls to enter winning holes, is varied depending on position, orientation, and angle of nails or pins arranged on the game board surface, as well as the interval between adjacent nails. Therefore, the adjustment of nails is an important operation for a pachinko shop. For a player, on the other hand, it is most important to find a pachinko game machine which has been adjusted to provide a higher probability of producing winning balls.
There has hitherto been known a pachinko game machine having a special winning hole called starter hole or "chucker" which causes a separate game to be started by a variable display device or a variable winning device when a game ball enters the special winning hole, so that a player may be given a chance for obtaining an increased score as a result of the separate game. In such pachinko game machines, it has been proposed that the results of the separate game should be according to a predetermined probability to give the chance for obtaining high scores by the separate game to more players.
However, even if a result of the separate game provides a high score to a player on the basis of a predetermined probability, it is not assured that a winning ball will enter the starter hole, and a probability of a particular result of the separate game varies according to the number of winning balls entered into the starter hole. Further, in order to match the game machine with a well-trained player or professional, the nails disposed near the starter hole can be adversely adjusted or the starter hole is disposed at a position where a winning ball is seldom obtained, so that the number of prize balls greatly varies depending on the skill of the player. Consequently, such a game machine lacks impartiality as a game designed for the unskilled public.